Passive spray system for aerosol removal in nuclear power plants

Abstract

This invention discloses a passive spray system for aerosol removal in nuclear power plants, comprising: a condensate collector, a guide pipe, a spray water tank, a spray pipe, a burst valve, and nozzles. The condensate collector is connected to the spray water tank via the guide pipe and is used to collect condensate within the containment. The spray water tank is connected to the nozzles via the spray pipes. The burst valve is installed on the spray pipes. When the pressure inside the containment reaches the activation trigger pressure of the burst valve, the burst valve opens, and water from the spray water tank flows into the nozzles through the spray pipes, where it is sprayed to remove aerosols from the containment. The beneficial effects of this system are as follows: compared with natural removal methods, this system provides more efficient removal of suspended aerosols within the containment; compared with active spray systems, this system does not require pumps and power supplies, and has higher reliability under accident conditions; this system can collect condensate near the walls, providing a more sustainable water source for the spray system.

Description

Technical Field

[0001] This invention belongs to the field of nuclear power plant safety design technology, specifically relating to a passive spraying system for aerosol removal in nuclear power plants. Background Technology

[0002] In severe nuclear power plant accidents, the containment vessel, as the last line of defense against radioactive contamination, generates a large amount of radioactive fission product aerosols within it. Controlling the amount of suspended aerosols within the containment vessel is an effective means of preventing the release and diffusion of radioactivity into the environment.

[0003] Currently, there are two main methods for controlling the amount of aerosol suspended in the containment: spray removal and natural removal. The characteristics of these two methods are as follows: (1) The spray method has the advantage of high removal efficiency, but the disadvantage is high cost. In addition, traditional spray systems are driven by pumps and require power supply. Under accident conditions, there is a risk that they cannot start successfully; (2) The natural removal method has the advantage that the removal process is completed by a naturally occurring process, which has high reliability. The disadvantage is that the aerosol removal efficiency is low and the safety margin provided is low. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to address the above-mentioned deficiencies in the prior art by providing a passive spray system for aerosol removal in nuclear power plants. The system is automatically activated by a rupture valve and can collect condensate generated by the passive residual heat discharge system of the containment, providing a long-term spray water source for the spray system.

[0005] The technical solution adopted to solve the technical problem of this invention is to provide a passive spraying system for aerosol removal in nuclear power plants, comprising: a condensate collector, a guide pipe, a spray water tank, a spray pipe, a burst valve, and a nozzle. The condensate collector is connected to the spray water tank through the guide pipe and is used to collect condensate inside the containment. The spray water tank is connected to the nozzle through the spray pipe. The burst valve is installed on the spray pipe. When the pressure inside the containment reaches the activation trigger pressure of the burst valve, the burst valve opens, and water in the spray water tank flows into the nozzle through the spray pipe, and the nozzle sprays water to remove aerosols inside the containment. The passive spraying system of this invention is installed inside the containment.

[0006] Preferably, the condensate collector is located below the heat exchanger inside the containment, and the condensate collector is used to collect the condensate obtained by condensation through the heat exchanger.

[0007] Preferably, the condensate collector includes at least one condensate collection tray, which is annular.

[0008] Preferably, the condensate collector includes at least two condensate collection trays that are evenly distributed below the heat exchanger.

[0009] Preferably, the spray tank is located in the center of the containment, and the height of the spray tank is lower than the height of the condensate collector.

[0010] Preferably, there are at least two nozzles, which are distributed radially in the containment.

[0011] Preferably, the rupture valve includes: a valve body, a valve inlet disposed on the valve body, a valve outlet disposed on the valve body, a valve disc disposed within the valve body, and a triggering assembly. The valve inlet is connected to the spray tank, the valve outlet is connected to the spray nozzle, and the triggering assembly is connected to the valve disc. The triggering assembly is subjected to the pressure inside the containment. When the pressure inside the containment reaches the activation triggering pressure of the rupture valve, the triggering assembly triggers the valve disc to open, and the valve inlet and valve outlet are connected.

[0012] Preferably, the valve disc is a piston, and the rupture valve further includes: a valve seat disposed within the valve body; the triggering assembly includes: a contact cavity disposed within the valve body, a spring end plug, a spring, and a pressure contact plate; one end of the spring is connected to the spring end plug, and the other end of the spring is connected to the first end of the piston; the pressure contact plate is disposed within the contact cavity, one end of the pressure contact plate is connected to the second end of the piston, and the other end of the pressure contact plate is connected to the contact cavity; a pressure channel is provided on the valve seat, one end of the pressure channel is connected to the gas pressure end of the containment; the spring end plug is slidably connected to the pressure channel; the piston is slidably connected to the pressure channel; a piston channel is provided in the contact cavity; the piston is slidably connected to the piston channel; the pressure within the contact cavity is less than the pressure within the containment; when the piston is within the pressure channel and the piston channel, the valve inlet and valve outlet are isolated; after the piston leaves the pressure channel, the valve inlet and valve outlet are connected.

[0013] Preferably, the passive spray system for aerosol removal in nuclear power plants further includes a first sealing element disposed between the compression spring end plug and the pressure channel. The first sealing element is disposed on the periphery of the compression spring end plug or the inner wall of the pressure channel, and is used to seal the gap between the compression spring end plug and the pressure channel.

[0014] Preferably, the passive spray system for aerosol removal in nuclear power plants further includes a second seal, disposed between the piston periphery and the piston channel. The second seal is disposed on the piston periphery or the inner wall of the piston channel and is used to seal the gap between the piston periphery and the piston channel.

[0015] Preferably, the passive spray system for aerosol removal in nuclear power plants further includes a limiting part disposed in the pressure channel, wherein the compression spring end plug is closer to the inside of the valve body than the limiting part, and the limiting part is used to limit the compression spring end plug so that the compression spring end plug is in the pressure channel.

[0016] Preferably, the piston includes: a piston body, a piston protrusion disposed on the piston body, the piston body being slidably connected to a piston channel, and the piston protrusion being slidably connected to a pressure channel.

[0017] Preferably, the pressure contact is V-shaped or U-shaped.

[0018] Preferably, the pressure inside the contact cavity is 0 to 1 atmosphere.

[0019] Compared to existing technologies, the passive spraying system for aerosol removal in nuclear power plants described in this invention offers the following advantages:

[0020] (1) Compared with natural removal methods, this system can provide more efficient removal of suspended aerosols inside the containment.

[0021] (2) Compared with the active sprinkler system, this system does not require pumps and power supply equipment, and has higher reliability in accident conditions.

[0022] (3) This system can collect condensate near the heat exchanger wall, providing a more durable water source for the spray system. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the passive spraying system for aerosol removal in nuclear power plants according to Embodiment 2 of the present invention;

[0024] Figure 2 This is a schematic diagram of the burst valve in Embodiment 2 of the present invention.

[0025] In the diagram: 1-Containment vessel; 2-Heat exchanger; 3-Condensate collection tray; 4-Guide pipe; 5-Spray water tank; 6-Break valve; 7-Spray head; 8-Pressure contact plate; 9-Piston; 91-Piston body; 92-Piston protrusion; 10-Valve inlet; 11-Containment vessel pressure end; 12-Valve outlet; 13-Compression spring; 14-Compression spring end plug; 15-Contact plate cavity; 16-Limiting part; 17-Pressure channel; 18-Piston channel; 19-Spray pipe. Detailed Implementation

[0026] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] The embodiments of this patent are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this patent, and should not be construed as limiting this patent.

[0028] Example 1

[0029] This embodiment provides a passive spraying system for aerosol removal in nuclear power plants, including: a condensate collector, a guide pipe, a spray water tank, a spray pipe, a rupture valve, and a nozzle. The condensate collector is connected to the spray water tank through the guide pipe and is used to collect condensate inside the containment. The spray water tank is connected to the nozzle through the spray pipe. The rupture valve is installed on the spray pipe. When the pressure inside the containment reaches the activation trigger pressure of the rupture valve, the rupture valve opens, and water in the spray water tank flows into the nozzle through the spray pipe, and water is sprayed through the nozzle to remove aerosols inside the containment.

[0030] Compared to existing technologies, the passive spraying system for aerosol removal in nuclear power plants in this embodiment offers the following advantages:

[0031] (1) Compared with natural removal methods, this system can provide more efficient removal of suspended aerosols inside the containment.

[0032] (2) Compared with the active sprinkler system, this system does not require pumps and power supply equipment, and has higher reliability in accident conditions.

[0033] (3) This system can collect condensate near the heat exchanger wall, providing a more durable water source for the spray system.

[0034] Example 2

[0035] like Figure 1 As shown, this embodiment provides a passive spray system for aerosol removal in a nuclear power plant, including: a condensate collector, a guide pipe 4, a spray water tank 5, a spray pipe 19, a burst valve 6, and a nozzle 7. The condensate collector is connected to the spray water tank 5 via the guide pipe 4 and is used to collect condensate within the containment 1. The spray water tank 5 is connected to the nozzle 7 via the spray pipe 19. The burst valve 6 is installed on the spray pipe 19. When the pressure inside the containment 1 reaches the activation trigger pressure of the burst valve 6, the burst valve 6 opens, and water from the spray water tank 5 flows into the nozzle 7 through the spray pipe 19, spraying water through the nozzle 7 to remove aerosols within the containment 1. In this embodiment, the passive spray system is installed inside the containment 1.

[0036] Preferably, the condensate collector is located below the heat exchanger 2 inside the containment 1, and the condensate collector is used to collect the condensate obtained by condensation through the heat exchanger 2.

[0037] Preferably, the condensate collector includes at least one condensate collection tray 3, which is annular. The condensate collection tray 3 is located below the heat exchanger 2 of the passive waste heat removal system within the containment 1 and can collect condensate near the heat exchanger 2.

[0038] The guide pipe 4 connects the condensate collection tray 3 and the spray water tank 5. The guide pipe 4 is straight to ensure that the condensate can flow smoothly to the spray water tank 5. The guide pipe 4 is inclined downwards.

[0039] Preferably, the condensate collector includes at least two condensate collection trays 3, which are evenly distributed below the heat exchanger 2. The heat exchanger 2 is the heat exchanger for the passive waste heat removal system within the containment 1.

[0040] Preferably, the spray tank 5 is located at the center of the containment 1, and the height of the spray tank 5 is lower than the height of the condensate collector.

[0041] Specifically, in this embodiment, the height of the spray tank 5 is slightly lower than the height of the condensate collection tray 3, which facilitates the automatic collection of condensate and ensures that the condensate in the condensate collection tray 3 flows in automatically by gravity.

[0042] This sprinkler tank 5 is filled with water, providing the initial water source for the passive sprinkler system. A burst valve 6 is located below the sprinkler tank 5. When the pressure in the containment vessel 1 reaches the activation trigger pressure, the burst valve 6 opens, and the sprinkler system begins operation.

[0043] Preferably, there are at least two nozzles 7, which are distributed radially in the containment 1.

[0044] Preferably, the burst valve 6 includes: a valve body, a valve inlet 10 disposed on the valve body, a valve outlet 12 disposed on the valve body, a valve disc disposed within the valve body, and a triggering assembly. The valve inlet 10 is connected to the spray tank 5, the valve outlet 12 is connected to the sprinkler head 7, and the triggering assembly is connected to the valve disc. The triggering assembly is subjected to the pressure inside the containment 1. When the pressure inside the containment 1 reaches the activation triggering pressure of the burst valve 6, the triggering assembly triggers the valve disc to open, connecting the valve inlet 10 and the valve outlet 12. The burst valve 6 is located below the spray tank 5.

[0045] like Figure 2As shown, preferably, the valve disc is a piston 9, and the burst valve 6 further includes: a valve seat disposed within the valve body; the triggering assembly includes: a contact cavity 15 disposed within the valve body, a spring end plug 14, a spring 13, and a pressure contact 8; one end of the spring 13 is connected to the spring end plug 14, and the other end of the spring 13 is connected to the first end of the piston 9; the pressure contact 8 is disposed within the contact cavity 15, one end of the pressure contact 8 is connected to the second end of the piston 9, and the other end of the pressure contact 8 is connected to the contact cavity 15; the valve seat has an opening... Pressure channel 17, one end of which is connected to the gas pressure end 11 of the containment, compression spring end plug 14 is slidably connected to pressure channel 17, piston 9 is slidably connected to pressure channel 17, contact cavity 15 has piston channel 18, piston 9 is slidably connected to piston channel 18, the pressure in contact cavity 15 is less than the pressure in containment 1, when piston 9 is in pressure channel 17 and piston channel 18, valve inlet 10 is isolated from valve outlet 12, after piston 9 leaves pressure channel 17, valve inlet 10 is connected to valve outlet 12.

[0046] The pressure contact 8 bends after reaching its pressure limit. After the pressure contact 8 bends, the piston 9 can move upwards. The upward movement is powered by the spring force of the compression spring 13 and the pressure within the contact cavity 15 where the pressure contact 8 is located. Specifically, in this embodiment, the pressure within the contact cavity 15 is negative.

[0047] The valve inlet 10 is connected to the spray water tank 5. When the burst valve 6 is opened, that is, when the piston 9 moves upward, the spray water can flow from the valve inlet 10 to the valve outlet 12.

[0048] The pressure at the gas pressure end 11 of the containment acts on the compression spring end plug 14, pushing it to move upward.

[0049] Valve outlet 12 is connected to spray pipe 19. When the rupture valve 6 is open, spray water flows into spray pipe 19 through it.

[0050] The compression spring 13 is located between the piston 9 and the compression spring end plug 14. Before the pressure in the containment 1 rises but reaches the start pressure of the spray system, the compression spring 13 contracts, providing some power for the piston 9 to move upward after the pressure contact plate 8 bends.

[0051] Specifically, when the rupture valve 6 is closed, the pressure contact plate 8 is in a straightened state and receives the pulling force of the piston 9. In this embodiment, the upper end face of the compression spring end plug 14 is connected to the compression spring 13, and the lower end face of the compression spring end plug 14 is in contact with the atmosphere of the containment 1. After the pressure of the containment 1 increases, the compression spring end plug 14 moves upward, the piston 9 moves upward, the pressure contact plate 8 bends, the pulling force of the piston 9 previously received by the pressure contact plate 8 disappears, and the pressure contact plate 8 is subjected to the pressure of the piston 9.

[0052] The contact cavity 15 is in a vacuum state to one atmosphere, which is negative pressure compared with the pressure inside the containment 1. After the pressure contact 8 bends, it provides part of the power for the upward movement of the piston 9.

[0053] The nozzles 7 are distributed radially in the containment 1 via the spray pipes 19 to ensure that the spray water fully covers the radial direction of the containment 1.

[0054] Preferably, the passive spray system for aerosol removal in nuclear power plants further includes a first sealing element disposed between the compression spring end plug 14 and the pressure channel 17. The first sealing element is disposed on the periphery of the compression spring end plug 14 or on the inner wall of the pressure channel 17, and is used to seal the gap between the compression spring end plug 14 and the pressure channel 17. Specifically, the first sealing element is a first O-ring. The first O-ring is disposed in a groove formed on the periphery of the compression spring end plug 14, or in a groove formed on the inner wall of the pressure channel 17.

[0055] Preferably, the passive spray system for aerosol removal in nuclear power plants further includes a second seal, disposed between the periphery of the piston 9 and the piston channel 18. The second seal is located on the periphery of the piston 9 or the inner wall of the piston channel 18, and is used to seal the gap between the periphery of the piston 9 and the piston channel 18. Specifically, the second seal is a second O-ring. The second O-ring is disposed within a groove formed on the periphery of the piston 9 or within a groove formed on the inner wall of the piston channel 18.

[0056] Preferably, the passive spray system for aerosol removal in nuclear power plants further includes a limiting part 16 disposed in the pressure channel 17, wherein the compression spring end plug 14 is closer to the inside of the valve body than the limiting part 16, and the limiting part 16 is used to limit the compression spring end plug 14 so that the compression spring end plug 14 is within the pressure channel 17.

[0057] Preferably, the piston 9 includes: a piston body 91 and a piston protrusion 92 disposed on the piston body 91. The piston body 91 is slidably connected to the piston channel 18, and the piston protrusion 92 is slidably connected to the pressure channel 17. The piston protrusion 92 limits the movement of the piston body 91, preventing the piston body 91 and the compression spring 13 from moving together into the contact cavity 15. After the pressure in the containment 1 increases, the compression spring end plug 14 moves upward, the piston 9 moves upward, the piston protrusion 92 leaves the pressure channel 17, and the valve inlet 10 connects with the valve outlet 12.

[0058] Preferably, the pressure contact 8 is V-shaped or U-shaped. Specifically, in this embodiment, the pressure contact 8 is V-shaped.

[0059] Preferably, the pressure inside the contact cavity 15 is 0 to 1 atmosphere.

[0060] Under nuclear power plant accident conditions, high-temperature, high-pressure steam will continuously be generated within containment 1, resulting in continuous condensation near the heat exchanger 2 of the passive residual heat removal system within containment 1. A condensate collection tray 3 located below heat exchanger 2 effectively collects the condensate. The condensate in the collection tray 3 flows through a guide pipe 4 into a spray water tank 5. Because water vapor is continuously generated within containment 1, this condensate collector provides a long-term supply of spray water for the spray system.

[0061] The main function of the spray pipe 19 and the nozzle 7 is to spray the water in the spray tank 5 and the collected condensate evenly and completely within the containment 1.

[0062] Compared to existing technologies, the passive spraying system for aerosol removal in nuclear power plants in this embodiment offers the following advantages:

[0063] (1) Compared with natural removal, this system can provide more efficient removal of suspended aerosols in containment 1.

[0064] (2) Compared with the active sprinkler system, this system does not require pumps and power supply equipment, and has higher reliability in accident conditions.

[0065] (3) This system can collect the condensate near the wall of heat exchanger 2, which can provide a more durable water source for the spray system.

[0066] Example 3

[0067] This embodiment provides a passive spraying system for aerosol removal in nuclear power plants, which differs from the spraying system in Embodiment 2 in the following ways:

[0068] The pressure contact is U-shaped.

[0069] Compared to existing technologies, the passive spraying system for aerosol removal in nuclear power plants in this embodiment offers the following advantages:

[0070] (1) Compared with natural removal methods, this system can provide more efficient removal of suspended aerosols inside the containment.

[0071] (2) Compared with the active sprinkler system, this system does not require pumps and power supply equipment, and has higher reliability in accident conditions.

[0072] (3) This system can collect condensate near the heat exchanger wall, providing a more durable water source for the spray system.

[0073] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A passive spraying system for aerosol removal in nuclear power plants, characterized in that, include: The containment system includes a condensate collector, a guide pipe, a spray tank, spray pipes, a burst valve, and sprinklers. The condensate collector is connected to the spray tank via the guide pipe and is used to collect condensate within the containment. The spray tank is connected to the sprinklers via the spray pipes. The burst valve is located on the spray pipes. When the pressure inside the containment reaches the burst valve's activation trigger pressure, the burst valve opens, allowing water from the spray tank to flow into the sprinklers through the spray pipes and spray water through the sprinklers to remove aerosols from the containment. The burst valve includes a valve body, a valve inlet on the valve body, a valve outlet on the valve body, a valve disc within the valve body, and a triggering assembly. The valve inlet is connected to the spray tank, the valve outlet is connected to the sprinklers, and the triggering assembly is connected to the valve disc. The triggering assembly is subjected to pressure inside the containment. When the pressure inside the containment reaches the burst valve's activation trigger pressure, the triggering assembly triggers the valve disc to open, connecting the valve inlet and valve outlet. The valve disc is a piston. The burst valve also includes a valve seat disposed within the valve body. The triggering assembly includes a contact cavity disposed within the valve body, a spring end plug, a spring, and a pressure contact plate. One end of the spring is connected to the spring end plug, and the other end is connected to the first end of the piston. The pressure contact plate is disposed within the contact cavity, with one end connected to the second end of the piston and the other end connected to the contact cavity. A pressure channel is provided on the valve seat, with one end of the pressure channel connected to the gas pressure end of the containment. The spring end plug is slidably connected to the pressure channel, and the piston is slidably connected to the pressure channel. A piston channel is provided in the contact cavity, and the piston is slidably connected to the piston channel. The pressure within the contact cavity is less than the pressure within the containment. When the piston is within the pressure channel and the piston channel, the valve inlet and valve outlet are isolated. After the piston leaves the pressure channel, the valve inlet and valve outlet are connected.

2. The passive spraying system for aerosol removal in nuclear power plants according to claim 1, characterized in that, The condensate collector is located below the heat exchanger inside the containment and is used to collect the condensate obtained by the heat exchanger.

3. The passive spraying system for aerosol removal in nuclear power plants according to claim 2, characterized in that, The condensate collector includes at least one condensate collection tray, which is annular.

4. The passive spraying system for aerosol removal in nuclear power plants according to claim 3, characterized in that, The condensate collector includes at least two condensate collection trays, which are evenly distributed below the heat exchanger.

5. The passive spraying system for aerosol removal in nuclear power plants according to claim 1, characterized in that, The spray tank is located in the center of the containment, and its height is lower than that of the condensate collector.

6. The passive spraying system for aerosol removal in nuclear power plants according to claim 1, characterized in that, There are at least two nozzles, which are distributed radially in the containment.

7. The passive spraying system for aerosol removal in nuclear power plants according to claim 1, characterized in that, It also includes a first sealing element, which is disposed between the compression spring end plug and the pressure channel. The first sealing element is disposed on the periphery of the compression spring end plug or the inner wall of the pressure channel. The first sealing element is used to seal the gap between the compression spring end plug and the pressure channel.

8. The passive spraying system for aerosol removal in nuclear power plants according to claim 1, characterized in that, It also includes a second seal, which is disposed between the piston periphery and the piston channel. The second seal is disposed on the piston periphery or the inner wall of the piston channel and is used to seal the gap between the piston periphery and the piston channel.

9. The passive spraying system for aerosol removal in nuclear power plants according to claim 1, characterized in that, It also includes a limiting part disposed in the pressure channel. The pressure spring end plug is closer to the inside of the valve body than the limiting part. The limiting part is used to limit the pressure spring end plug so that the pressure spring end plug is in the pressure channel.

10. The passive spraying system for aerosol removal in nuclear power plants according to claim 1, characterized in that, Pistons include: The piston body and the piston protrusion disposed on the piston body are slidably connected to the piston channel and the piston protrusion is slidably connected to the pressure channel.

11. The passive spraying system for aerosol removal in nuclear power plants according to claim 1, characterized in that, The pressure contact is either "V" or "U" shaped.

12. The passive spraying system for aerosol removal in nuclear power plants according to claim 1, characterized in that, The pressure inside the contact cavity is 0 to 1 atmosphere.

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